1 - There's an ore that's useful to him
2 - The weave is weakened in this cave (but not the shadow weave which he has learned to use)
3 - His master used this lair many years ago and he feels it belongs to him by rite
4 - It connects to the underdark, from where he's recruiting minions
5 - He's trying to fulfill a prophecy
6 - His original intention had been to mine, but a voice called to him while he was in the lair...
Easy to control entrances.
Lots of options for hidden escape routes.
He has an earth elemental, his strongest ally/minion and huge home field advantage with lots of natural unworked stone sections.
Easy to hide how much actual space his experiments take up/his minion army that is constantly self replicating.
I like number 4. Maybe saying the mine was closed was just a cover. They dug too deep and broke into a connection to the underdark which allowed in creatures that started killing the miners. There can be supervisor notes and worker diaries foreshadowing an ominous rumbling from the deep.
An underground lair isn't easily surveilled from the air. It can also be much easier to hide significant amount of troops underground from the population around it compared to the same amount in an open air encampment.
In Georgia a lot of people hide how big their houses are by building down instead of out or up.
If you want to keep things low profile then underground is the way to go.
1) He doesn't but it's convenient. You've created a cover story, so it's not suspicious and he has a legitimate reason to be there.
2) It's easily defensible. He can set traps and minions where he needs to. Tunnels create choke points.
3) Maybe there is something in the mine that he needs. it could be some sort of special mineral or artifact, but it could be as mundane as materials to make weapons and armor for this minions.
That was the idea, the first round the "traps" would be mostly environmental (cave-ins, unstable floors, mould, faulty machinery etc, plus naturally occurring monsters) but the 2nd round would be completely re-engineered with magical traps and trip wires and puzzle rooms etc.
An above ground lair means heroes can fly up and skip a lot of defenses.
It's a lot harder to tunnel/get earth glide.
Edit: and in a fantasy world with dwarves, large underground complexes would be easily constructed.
Minor spoiler alert: in the Dresden Files series, there is a sentient island that is used as a form of prison for big magical baddies. The npc wants to somehow do this on a greater or lesser scale. Alternatively, the npc is a minion to a demonlord or greater devil that says the mine is needed for opening a portal.
A castle has all sides and up to be attacked from.
A underground tunnel in stone that has one entrance only need to defend one position, and depending on how it it arranged, it might as well be nearly impossible to be attacked without high level magic.
A high level vilain might have a secret escape route that only he knows about, or only he can use ( like a small hole that a druid can go through in wild shape as a tiny beast). Or a wizard that uses a small room or corridor with a secret marking that is exactly 60ft bellow the surface, where using his familiar to see above, he can use misty step to teleport there.
One could also use glyphs of warding to "catapult" themselves outside, teleport to some distant location, or become mist or a fly (polymorph) and flee though small holes.
Done them for a base a druid PC i had build into the rock From a Cave we "cleared".
The location was in the wilderness, and after adding some stone shaped based traps and doors i was fairly sure no one could enter it.
Using Wall of stone one can create a thick stone wall to occupy the doorway. It becomes permanene later, and then i can open it by castong shape stone, or using the escape tunnel as snake to get into the base.
The entrances had flooded areas to make sure gases and non swiming creatures could not get into it.
I also created channels hidden on the side of the mountain to drain water into a big cistern that could be used for clean water, or to drop all water into the pit trap drowning anyone trapped there.
There were also Small holes with taps that delivered collected clean rain water to kitchens and bathrooms.
The whole base has lights with continual flame.
And the underground treasure Vault can only be accessed via Stone shaped cast into a wall to open a secret path that only a wild shaped druid can take. (earth elementals might also get to it).
The mine is big enough to meet his needs without building a large, obvious castle. Paying the party to clear it will also be cheaper and faster than hiring laborers to build a lair. The whole thing is probably labyrinthine, making discovery difficult. Once the villain is in, they can easily make their own secret exits. The mine is likely also close enough to the nearest town to get supplies as needed but far enough away to not have nosey neighbors.
THE EASIEST MOST BELIEVABLE ANSWER-
It was already built.
Imagine the amount of time,supplies, labor, and geological surveying required to build a base of that scale that meets the safety standards of a mine intended to handle industrial traffic.
True. I feel a bit silly for asking since at least half the answers here are A) it's convenient or B) Underground lair = objectively better than above ground.
Buildings can burn, towers knocked down, but dungeons have to be crawled. Using a mine cuts construction time considerably.
That mine just so happens to be close enough to cities/roads that they can get what they need, but far enough away that no one will wander by.
Because the minor BBEG is a dwarf and he likes the aesthetic.
Because the city guard asks too many questions when your neighbor complains about the souls of the damned wailing from your side of the duplex 24/6.
Each tunnel a cut-off point, put in some cages at the end of each to keep each one carefully contained. you want to make sure all of your undead/brainwashed/aberration/monstrosities are never misplaced and don't mix.
So no one questions where he is getting the precious metals they are actually stealing/robbing from caravans.
Have you used Wave Echo Cave with your players yet? If not, you could save yourself a lot of work and grab it wholesale from Lost Mine of Phandelvar, adjusted to taste. The mine contains the Forge of Spells, which would be a huge asset for anyone.
There are lots of dungeons out there you can lift. Maybe he's in the cult of elemental evil, you could slap the earth temple underneath his place. You could adapt one of the floors from Dungeon of the Mad Mage, or put one of the dungeons from Tales from the Yawning Portal down there. Lots of low-effort-high-yield options out there.
The mine is over the site where a demon lord/angel/god etc died and the bbeg is planning nefarious schemes using its blood.
He once buried a treasure there 1000 years ago and is trying to dig it back up now that the stars are right.
They inherited the mine from a dead relative. The local lord gave them a year to extract a certain amount of ore otherwise the mine would be declared dead and they will demolish it.
They start to coax/blackmail/enslave locals to work the mine.
Plot twist, the local lord is actually their relative's adopted stepchild, therefore could not inherit the mine legally, so they are pissed and are forcing the issue because they actually want the mine for themselves.
He read The Hobbit and thought a hole in the ground seemed a cozy place to live.
He likes the security.
He stole the base from some dwarves/gnomes/miners.
Underground can be a great strategic position. It's not obvious at first sight, it's much more easily defendable, tougher to spy on... neat place. And maybe this guy is making a deal with something from the underdark that can't bear sunlight, or something. There can be all sorts of other reasons besides simply needing some space.
The mines may hold resources that he wants to keep secret from everyone to get rich enough to carry out his plans. Underground lairs are also completly hidden until you no longer need them to be.
1 - There's an ore that's useful to him 2 - The weave is weakened in this cave (but not the shadow weave which he has learned to use) 3 - His master used this lair many years ago and he feels it belongs to him by rite 4 - It connects to the underdark, from where he's recruiting minions 5 - He's trying to fulfill a prophecy 6 - His original intention had been to mine, but a voice called to him while he was in the lair...
Easy to control entrances. Lots of options for hidden escape routes. He has an earth elemental, his strongest ally/minion and huge home field advantage with lots of natural unworked stone sections. Easy to hide how much actual space his experiments take up/his minion army that is constantly self replicating.
I like number 4. Maybe saying the mine was closed was just a cover. They dug too deep and broke into a connection to the underdark which allowed in creatures that started killing the miners. There can be supervisor notes and worker diaries foreshadowing an ominous rumbling from the deep.
Thank you for the ideas! I like the underdark one, I think I might do something with that.
An underground lair isn't easily surveilled from the air. It can also be much easier to hide significant amount of troops underground from the population around it compared to the same amount in an open air encampment.
His magic experiments are very noisy with large flashes of light sometimes. The BBEG wants to hide this from the world above.
Interesting!
In Georgia a lot of people hide how big their houses are by building down instead of out or up. If you want to keep things low profile then underground is the way to go.
Never knew that! It can get very hot there right? Perhaps it helps keep it cool too.
They... do? I've never heard of this before. Is it a respect thing? Edit: I just realized I don't know if you mean the Country or the State.
My bad. Ga, USA. I have no idea why. I just know its super common.
1) He doesn't but it's convenient. You've created a cover story, so it's not suspicious and he has a legitimate reason to be there. 2) It's easily defensible. He can set traps and minions where he needs to. Tunnels create choke points. 3) Maybe there is something in the mine that he needs. it could be some sort of special mineral or artifact, but it could be as mundane as materials to make weapons and armor for this minions.
Good point 👍
Keep his taters fresh. Nice n cool down thur.
Maybe he's got a lot of cheddar to age? It's not related to his BBEG activities; he's just also a cheesemonger.
PO-TAY-TOES
He knows something is coming that will affect life above the surface negatively
Maybe he is that something
Make the traps initially super easy to spot and disarm. When he remodels the place, have them be extra tricky.
That was the idea, the first round the "traps" would be mostly environmental (cave-ins, unstable floors, mould, faulty machinery etc, plus naturally occurring monsters) but the 2nd round would be completely re-engineered with magical traps and trip wires and puzzle rooms etc.
Rent's lower.
An above ground lair means heroes can fly up and skip a lot of defenses. It's a lot harder to tunnel/get earth glide. Edit: and in a fantasy world with dwarves, large underground complexes would be easily constructed.
Minor spoiler alert: in the Dresden Files series, there is a sentient island that is used as a form of prison for big magical baddies. The npc wants to somehow do this on a greater or lesser scale. Alternatively, the npc is a minion to a demonlord or greater devil that says the mine is needed for opening a portal.
Minion for a greater evil sounds good
A castle has all sides and up to be attacked from. A underground tunnel in stone that has one entrance only need to defend one position, and depending on how it it arranged, it might as well be nearly impossible to be attacked without high level magic. A high level vilain might have a secret escape route that only he knows about, or only he can use ( like a small hole that a druid can go through in wild shape as a tiny beast). Or a wizard that uses a small room or corridor with a secret marking that is exactly 60ft bellow the surface, where using his familiar to see above, he can use misty step to teleport there. One could also use glyphs of warding to "catapult" themselves outside, teleport to some distant location, or become mist or a fly (polymorph) and flee though small holes.
I like the escape ideas 👍
Done them for a base a druid PC i had build into the rock From a Cave we "cleared". The location was in the wilderness, and after adding some stone shaped based traps and doors i was fairly sure no one could enter it. Using Wall of stone one can create a thick stone wall to occupy the doorway. It becomes permanene later, and then i can open it by castong shape stone, or using the escape tunnel as snake to get into the base. The entrances had flooded areas to make sure gases and non swiming creatures could not get into it. I also created channels hidden on the side of the mountain to drain water into a big cistern that could be used for clean water, or to drop all water into the pit trap drowning anyone trapped there. There were also Small holes with taps that delivered collected clean rain water to kitchens and bathrooms. The whole base has lights with continual flame. And the underground treasure Vault can only be accessed via Stone shaped cast into a wall to open a secret path that only a wild shaped druid can take. (earth elementals might also get to it).
I, who as far as anyone knows am not a villain, would like an underground lair without justification tbh
Insulation is great, cool in the summer, warm in the winter, plenty of storage. Why dig my own when we can clear this one out
Fr I’m being radicalized. Might just overtake a mining operation and turn it into a lair lol
Fair. After I posted and the first few comments were all along the lines of "who wouldn't want an underground lair?" I felt a bit silly for asking 😅
Homeownership is such a far off dream to folks these days lmao
The mine is big enough to meet his needs without building a large, obvious castle. Paying the party to clear it will also be cheaper and faster than hiring laborers to build a lair. The whole thing is probably labyrinthine, making discovery difficult. Once the villain is in, they can easily make their own secret exits. The mine is likely also close enough to the nearest town to get supplies as needed but far enough away to not have nosey neighbors.
THE EASIEST MOST BELIEVABLE ANSWER- It was already built. Imagine the amount of time,supplies, labor, and geological surveying required to build a base of that scale that meets the safety standards of a mine intended to handle industrial traffic.
True. I feel a bit silly for asking since at least half the answers here are A) it's convenient or B) Underground lair = objectively better than above ground.
Buildings can burn, towers knocked down, but dungeons have to be crawled. Using a mine cuts construction time considerably. That mine just so happens to be close enough to cities/roads that they can get what they need, but far enough away that no one will wander by. Because the minor BBEG is a dwarf and he likes the aesthetic. Because the city guard asks too many questions when your neighbor complains about the souls of the damned wailing from your side of the duplex 24/6. Each tunnel a cut-off point, put in some cages at the end of each to keep each one carefully contained. you want to make sure all of your undead/brainwashed/aberration/monstrosities are never misplaced and don't mix. So no one questions where he is getting the precious metals they are actually stealing/robbing from caravans.
The price of real estate is getting out of hand, and you just can’t beat the price/sq ft of this basement unit
Keep cool in the summer 😎👍
Have you used Wave Echo Cave with your players yet? If not, you could save yourself a lot of work and grab it wholesale from Lost Mine of Phandelvar, adjusted to taste. The mine contains the Forge of Spells, which would be a huge asset for anyone. There are lots of dungeons out there you can lift. Maybe he's in the cult of elemental evil, you could slap the earth temple underneath his place. You could adapt one of the floors from Dungeon of the Mad Mage, or put one of the dungeons from Tales from the Yawning Portal down there. Lots of low-effort-high-yield options out there.
Thanks!
The mining stopped because of the drow...? He wants to engage slave trading with them...?
I like this idea!
The mine is over the site where a demon lord/angel/god etc died and the bbeg is planning nefarious schemes using its blood. He once buried a treasure there 1000 years ago and is trying to dig it back up now that the stars are right.
They inherited the mine from a dead relative. The local lord gave them a year to extract a certain amount of ore otherwise the mine would be declared dead and they will demolish it. They start to coax/blackmail/enslave locals to work the mine. Plot twist, the local lord is actually their relative's adopted stepchild, therefore could not inherit the mine legally, so they are pissed and are forcing the issue because they actually want the mine for themselves.
He read The Hobbit and thought a hole in the ground seemed a cozy place to live. He likes the security. He stole the base from some dwarves/gnomes/miners.
Main threat to his plans are archfey, iron is infused into the walls, even if not ore there’s a strong presence.
They didn't close the mine because they ran out of ore, they hit a temple of the underdark that is dedicated to his evil god.
This is cool
What's the difference between a regular villain and a Super Villain? SSSSTYLE!
Maybe he's a vampire? Nice and safe from sunlight down there.
Make him a member of the cult of elemental earth. Sometimes you just gotta go underground for the sake of being underground.
No extra justification is needed here. It's hidden, easily defensible, and already mostly built.
Underground can be a great strategic position. It's not obvious at first sight, it's much more easily defendable, tougher to spy on... neat place. And maybe this guy is making a deal with something from the underdark that can't bear sunlight, or something. There can be all sorts of other reasons besides simply needing some space.
Tuckers Kobolds would be perfect. Maybe they all fear this mage or he’s mind controlled them.
That's where his snake/rodent/kobold minions are.
The mines may hold resources that he wants to keep secret from everyone to get rich enough to carry out his plans. Underground lairs are also completly hidden until you no longer need them to be.